Zeolite, manufacturing method of the same, and catalytic cracking catalyst of paraffin

ABSTRACT

A MSE-type zeolite which has a Si/Al ratio of 5 or more, is a proton-type zeolite, and is obtained by transforming a raw material MSE-type zeolite synthesized without using a structure directing agent into an ammonium-type zeolite through ion exchange, then, exposing the MSE-type zeolite to water vapor, and subjecting the exposed MES-type zeolite to an acid treatment.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.13/813,104, filed on Jan. 29, 2013 now U.S. Pat. No. 9,238,219, which isa 371 of International Application No. PCT/JP2012/080308, filed on Nov.22, 2012, which claims the benefit of priority from the prior JapanesePatent Application No. 2011-258328, filed on Nov. 25, 2011, JapanesePatent Application No. 2011-258329, filed on Nov. 25, 2011 and JapanesePatent Application No. 2012-255811, filed on Nov. 22, 2012, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a beta-type zeolite and a MSE-typezeolite. The beta-type zeolite and the MSE-type zeolite of the inventionare promising substances as a solid acid catalyst or an adsorbent, and,in more detail, are particularly promising as a catalytic crackingcatalyst of paraffin, for example, a cracking catalyst of a long-chainhydrocarbon in the petrochemical industry. Also, the beta-type zeoliteand the MSE-type zeolite are promising substances as a hydrocarbon trapfor purifying the exhaust gas from an internal-combustion engine. Inaddition, the invention relates to a manufacturing method of a beta-typezeolite and a MSE-type zeolite having an increased Si/Al ratio from abeta-type zeolite and a MSE-type zeolite as raw materials.

BACKGROUND ART

The beta-type zeolite is a useful substance as a solid acid catalyst oran adsorbent, and, currently, a large amount of the beta-type zeolite isglobally used as a catalyst in the petrochemical industry or ahydrocarbon trap for purifying the exhaust gas of an internal-combustionengine. A variety of synthesizing methods of a beta-type zeolite havebeen proposed. An ordinary method is a method in which a compoundincluding tetraethylammonium ions is used as a structure directing agent(hereinafter abbreviated to “organic SDA”). Such a method is describedin, for example, Patent Citation 1 below. However, although the compoundincluding tetraethylammonium ions is expensive, most of the excessiveportion is decomposed after completion of the crystallization of abeta-type zeolite, and decomposition is the only method that can removethe portion incorporated into crystals, and therefore it is not possibleto collect and recycle the compound. Therefore, a beta-type zeolitemanufactured using the above method is expensive. Furthermore, sincetetraethylammonium ions are incorporated into crystals, it is necessaryto remove tetraethylammonium ions through firing when a beta-typezeolite is used as an adsorbent or a catalyst. The exhaust gas at thistime causes environmental contamination, and a large amount of achemical is required for a detoxifying treatment of a synthesis motherliquid. As such, since the synthesizing method of a beta-type zeoliteusing tetraethylammonium ions is a manufacturing method which is notonly expensive, but also causes a large environmental load, there hasbeen a demand for realization of a manufacturing method in which theorganic SDA is not used.

Under the above circumstance, in recent years, a synthesizing method ofa beta-type zeolite in which the organic SDA is not used has beenproposed in Patent Citation 2. In the document, a silica source, analumina source, an alkali source and water are mixed so as to form areaction mixture having a specific composition; a beta-type zeolite notincluding an organic compound which has a SiO₂/Al₂O₃ ratio of 8 to 30and an average particle diameter of 150 nm or more is used as a seedcrystal, the beta-type zeolite is added to the reaction mixture at aproportion of 0.1 mass % to 20 mass % with respect to the silicacomponent in the reaction mixture; and the reaction mixture to which theseed crystal is added is enclosure-heated at 100° C. to 200° C., therebysynthesizing a beta-type zeolite without using the organic SDA.

However, in a case in which the beta-type zeolite is used as a catalystin the petrochemical industry or a hydrocarbon trap for purifying theexhaust gas of an internal-combustion engine, it is advantageous toincrease the Si/Al ratio from the viewpoint of performance improvement.A method for increasing the Si/Al ratio in the beta-type zeolite isdescribed in, for example, Patent Citation 3, and a method in which awater vapor treatment and an acid treatment are carried out sequentiallyis known.

[Patent Citation 1] U.S. Pat. No. 3,308,069

[Patent Citation 2] Pamphlet of the International Publication No.2011/013560

[Patent Citation 3] Japanese Patent Application Laid-Open No.2010-215434

DISCLOSURE OF INVENTION Technical Problem

However, there is a case in which, when only the Si/Al ratio of thebeta-type zeolite is increased, the catalytic activity of the beta-typezeolite degrades during use at a high temperature. In addition, there isthe same problem in a MSE-type zeolite which is similar to the beta-typezeolite in the structure and various properties, such as catalystcharacteristics.

An object of the invention is to provide a zeolite which can solve avariety of the above disadvantages of the related art, and amanufacturing method of the same.

Technical Solution

The invention solves the above problem by providing a beta-type zeolitewhich has a substantially octahedral shape, has a Si/Al ratio of 5 ormore, and is a proton-type zeolite.

In addition, the invention provides a MSE-type zeolite which is obtainedby transforming a raw material MSE-type zeolite, which has a Si/Al ratioof 5 or more, is a proton-type, and is synthesized without using astructure directing agent, into an ammonium-type zeolite through ionexchange, then, exposing the MSE-type zeolite to water vapor, andsubjecting the exposed beta-type zeolite to an acid treatment.

In addition, the invention provides a catalytic cracking catalyst ofparaffin which includes the beta-type zeolite and the MSE-type zeolite.

In addition, the invention provides a manufacturing method of abeta-type zeolite in which a raw material beta-type zeolite istransformed into an ammonium-type zeolite through ion exchange, then,the beta-type zeolite is exposed to water vapor, and the exposedbeta-type zeolite is subjected to an acid treatment, thereby obtaining abeta-type zeolite having an increased Si/Al ratio, wherein a beta-typezeolite synthesized without using a structure directing agent is used asthe raw material beta-type zeolite to be ion-exchanged.

Furthermore, the invention provides a manufacturing method of a MSE-typezeolite in which a raw material MSE-type zeolite is transformed into anammonium-type zeolite through ion exchange, then, the MSE-type zeoliteis exposed to water vapor, and the exposed MSE-type zeolite is subjectedto an acid treatment, thereby obtaining a MSE-type zeolite having anincreased Si/Al ratio, wherein a MSE-type zeolite synthesized withoutusing a structure directing agent is used as the raw material MSE-typezeolite to be ion-exchanged.

Advantageous Effects

According to the invention, a beta-type zeolite and a MSE-type zeolite,which have a high catalytic activity and are not easily deactivated, areprovided. In addition, according to the invention, it is possible toeasily manufacture a beta-type zeolite and a MSE-type zeolite having ahigh Si/Al ratio without breaking the crystal structure of the zeolites.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing an apparatus used during exposure ofa beta-type zeolite to water vapor.

FIG. 2A is a scanning electron microscopic photograph of a beta-typezeolite synthesized without using an organic structure directing agent.

FIG. 2B is a scanning electron microscopic photograph of the beta-typezeolite shown in FIG. 2A after dealumination (Example 1).

FIG. 3 shows X-ray diffraction diagrams of beta-type zeolites obtainedin Examples 1 to 5 and Comparative example 1.

FIG. 4A is a scanning electron microscopic photograph of a beta-typezeolite synthesized using an organic structure directing agent.

FIG. 4B is a scanning electron microscopic photograph of the beta-typezeolite shown in FIG. 4A after dealumination (Comparative example 3).

FIG. 5 shows X-ray diffraction diagrams of beta-type zeolites obtainedin Comparative examples 2 and 3.

FIG. 6 is a schematic view of an apparatus for evaluating the catalyticactivity of the beta-type zeolite.

FIG. 7 is a graph showing the temperature dependency of the inversionrate when cracking of hexane is carried out using beta-type zeolitesobtained in examples and comparative examples as catalysts.

FIG. 8 is a graph showing the time dependency of the inversion rate whencracking of hexane is carried out using beta-type zeolites obtained inthe examples and the comparative examples as catalysts.

FIG. 9 shows X-ray diffraction diagrams of beta-type zeolites obtainedin Examples 6 to 8.

FIG. 10 shows X-ray diffraction diagrams of beta-type zeolites obtainedin Examples 9 to 16.

FIG. 11 shows X-ray diffraction diagrams of beta-type zeolites obtainedin Examples 17 and 18.

FIG. 12 shows X-ray diffraction diagrams of MSE-type zeolites obtainedin Example 19 and Comparative examples 4 and 5.

FIG. 13 is a graph showing the time dependency of the inversion ratewhen cracking of hexane is carried out using MSE-type zeolites obtainedin the examples and the comparative examples as catalysts.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the invention will be described in detail. In thedescription below, the “zeolite” indicates either one or both of a“beta-type zeolite” and a “MSE-type zeolite” according to the context.Among the beta-type zeolite and the MSE-type zeolite of the invention,the beta-type zeolite has a substantially octahedral appearanceconfiguration. In the past, there were known beta-type zeolites having alow Si/Al ratio and a substantially octahedral appearance configuration,but there were no known beta-type zeolites having a high Si/Al ratio anda substantially octahedral appearance configuration. The reason isconsidered to be that, since there are many cases in which the beta-typezeolite having a high Si/Al ratio is obtained using the organic SDA, thebeta-type zeolite does not move into a growth mode of a substantiallyoctahedral crystal due to the generation of nuclei induced from theorganic SDA.

The beta-type zeolite and the MSE-type zeolite of the invention are highsilica zeolites having a Si/Al ratio of 5 or more. Since having theabove Si/Al ratio, the beta-type zeolite and the MSE-type zeolite of theinvention are useful as a catalyst used at a high temperature, such as acracking catalyst of a long-chain hydrocarbon (for example, hexane) inthe petrochemical industry or a catalyst for purifying the exhaust gasof an internal-combustion engine. There have been known beta-typezeolites and MSE-type zeolites having a Si/Al ratio of 5 or more, butthe appearance configurations of the zeolites are irregular, and,particularly, there has not been known a beta-type zeolite having asubstantially octahedral shape like the invention. The Si/Al ratios ofthe beta-type zeolite and the MSE-type zeolite of the invention arepreferably higher from the viewpoint of the catalytic activity and thelike. Specifically, the Si/Al ratio is preferably 14 or more, morepreferably 40 or more, and particularly preferably 55 or more. The upperlimit value of the Si/Al ratio is not particularly limited; however,when the upper limit is 200, preferably 190, and particularly 150, asufficiently satisfactory catalytic activity and the like can beobtained.

As described above, the beta-type zeolite of the invention ischaracterized by both (i) having an appearance configuration of asubstantially octahedral shape and (ii) having a Si/Al ratio of 5 ormore. The beta-type zeolite which thus far has been known is equippedwith only one of (i) and (ii) as described above, and there has been nobeta-type zeolite equipped with both (i) and (ii). In addition, theinventors found that a beta-type zeolite equipped with both (i) and (ii)has a high catalytic activity, and the activity is not easilydeactivated even at a high temperature, and completed the invention.Meanwhile, the MSE-type zeolite is characterized by having a Si/Al ratioof 5 or more. A MSE-type zeolite having the above Si/Al ratio has a highcatalytic activity, and the activity is not easily deactivated even at ahigh temperature, similarly to the beta-type zeolite.

The beta-type zeolite and the MSE-type zeolite of the inventionadvantageously have a Brensted acid site in order to be used as avariety of catalysts. From the above viewpoint, the zeolites of theinvention are proton-type zeolites. However, the zeolites of theinvention may include a small amount of ammonium ions or alkali metalions within a range in which the effects of the invention are notimpaired.

The average particle diameters of the beta-type zeolite and the MSE-typezeolite of the invention are preferably 0.2 μm to 2.0 μm, and morepreferably 0.5 μm to 1.0 μm. In addition, the BET specific surface areais 400 m²/g to 650 m²/g, preferably 500 m²/g to 650 m²/g, and morepreferably 550 m²/g to 650 m²/g. Furthermore, the volume of a micro holeis preferably 0.10 m³/g to 0.28 m³/g, and more preferably 0.15 m³/g to0.25 m³/g. The specific surface area and the volume are measured byusing a BET surface area measuring apparatus.

The beta-type zeolite of the invention preferably has diffraction peaksin at least the locations described in Tables 1 and 2 below in thediffraction pattern obtained through X-ray diffraction in which CuKα1rays are used. Meanwhile, Table 1 shows the diffraction patterns, andTable 2 shows preferable peak intensity ratios. In Table 1, “vs”indicates an extremely strong relative intensity (80% to 100%), “s”indicates a strong relative intensity (60% to 80%), “m” indicates anintermediate relative intensity (40% to 60%), and “w” indicates a weakrelative intensity (0% to 40%). In Table 2, the peak intensity (%)refers to a relative intensity when the peak intensity of the maximumpeak in the diffraction pattern is set to 100.

TABLE 1 Location of peak 2θ (°) Relative intensity 21.08-21.58 w22.12-22.62 vs 25.00-25.50 w 26.80-27.30 w 28.38-28.88 w 29.26-29.86 w30.00-30.70 w 32.92-33.62 w 43.00-43.85 w

TABLE 2 Location of peak 2θ (°) Peak intensity (%) 21.08-21.58 10-30 22.12-22.62 100 25.00-25.50 8-28 26.80-27.30 7-27 28.38-28.88 5-2529.26-29.86 7-37 30.00-30.70 2-17 32.92-33.62 4-19 43.00-43.85 3-18

The MSE-type zeolite of the invention preferably has diffraction peaksin at least the locations described in Tables 3 and 4 below in thediffraction pattern obtained through X-ray diffraction in which CuKα1rays are used. Meanwhile, Table 3 shows the diffraction patterns, andTable 4 shows preferable peak intensity ratios. In Table 3, “vs”indicates an extremely strong relative intensity (80% to 100%), “s”indicates a strong relative intensity (60% to 80%), “m” indicates anintermediate relative intensity (40% to 60%), and “w” indicates a weakrelative intensity (0% to 40%). In Table 4, the peak intensity (%)refers to a relative intensity when the peak intensity of the maximumpeak in the diffraction pattern is set to 100.

TABLE 3 Location of peak 2θ (°) Relative intensity 6.36-6.56 m-w6.67-6.87 m-w 7.93-8.23 w 8.55-8.85 m-w 9.47-9.77 s, m, w 10.59-10.89 w13.43-13.73 w 14.60-14.90 w 15.67-15.97 w 17.23-17.53 w 19.29-19.59 m-w19.73-20.03 w 20.27-20.67 w 20.75-21.15 w 21.41-21.81 vs 21.53-21.93 s22.29-22.69 s-m 22.79-23.19 s 23.09-23.49 w 25.52-25.92 w 25.90-26.30m-w 26.16-26.56 w 26.57-27.07 w 27.24-24.64 m 27.87-28.37 w 28.51-29.01w 28.90-29.40 w 29.47-29.97 w 29.96-30.46 m-w 30.53-31.03 m-w

TABLE 4 Location of peak 2θ (°) Peak intensity (%) 6.36-6.56 28-556.67-6.87 34-51 7.93-8.23 24-38 8.55-8.85 20-48 9.47-9.77 33-6110.59-10.89 16-31 13.43-13.73 16-24 14.60-14.90 12-17 15.67-15.97  9-1417.23-17.53 10-16 19.29-19.59 38-52 19.73-20.03 22-37 20.27-20.67 17-2420.75-21.15 14-22 21.41-21.81 100 21.53-21.93 68-87 22.29-22.69 53-6722.79-23.19 72-89 23.09-23.49 19-25 25.52-25.92 18-28 25.90-26.30 27-4226.16-26.56 20-27 26.57-27.07 17-37 27.24-24.64 42-56 27.87-28.37 23-3428.51-29.01 14-24 28.90-29.40 18-36 29.47-29.97 15-29 29.96-30.46 19-4130.53-31.03 22-41

The beta-type zeolite is preferably manufactured by dealuminating abeta-type zeolite having a substantially octahedral shape and a lowSi/Al ratio. Meanwhile, the MSE-type zeolite is preferably manufacturedby dealuminating a MSE-type zeolite having a low Si/Al ratio.Specifically, a preferable manufacturing method of the beta-type zeoliteof the invention includes three processes of (1) an ion exchangetreatment process of a raw material beta-type zeolite, (2) a process ofexposing the ion-exchanged raw material beta-type zeolite to watervapor, and (3) an acid treatment process of the raw material beta-typezeolite which has been exposed to water vapor. A preferablemanufacturing method of the MSE-type zeolite of the invention is thesame as above. Therefore, hereinafter, the manufacturing method of azeolite of the invention will be described using the preferablymanufacturing method of the beta-type zeolite as an example.

(1) The Ion Exchange Treatment Process of a Raw Material Beta-TypeZeolite

The raw material beta-type zeolite generally includes an alkali metalsuch as sodium. Since the beta-type zeolite including an alkali metalhas a difficulty in exhibiting desired characteristics in a case inwhich the zeolite is used as a catalyst in the petrochemical industry ora hydrocarbon trap for purifying the exhaust gas of aninternal-combustion engine, the alkali metal included in the rawmaterial beta-type zeolite is removed through ion exchange, and thezeolite is transformed into an ammonium-type beta-type zeolite.

The raw material beta-type zeolite which is subjected to an ion exchangetreatment has a low Si/Al ratio of, for example, 4 to 100, preferably 4to 8, and more preferably 5 to 7. This is because it is easy tosynthesize a beta-type zeolite having the above low Si/Al ratio as abeta-type zeolite having a substantially octahedral shape.

As a result of studies by the inventors, it was found that it isadvantageous to use a beta-type zeolite synthesized without using theorganic SDA (hereinafter also referred to as “OSDA-free beta-typezeolite”) as the raw material beta-type zeolite. When the OSDA-freebeta-type zeolite is used as the raw material beta-type zeolite, it iseasy to synthesize a beta-type zeolite having a substantially octahedralshape. In addition, even when the OSDA-free beta-type zeolite having alow Si/Al ratio is dealuminated, the substantially octahedral shape ismaintained, and the catalytic activity of the obtained beta-type zeolitehaving a high Si/Al ratio is not easily deactivated. Furthermore, use ofthe OSDA-free beta-type zeolite is advantageous since the organic SDA isnot used, and is also advantageous from the viewpoint of economicefficiency and environmental load.

Meanwhile, as a result of studies by the inventors, it is found that theOSDA-free beta-type zeolite has a crystal structure which is easilybroken when the Si/Al is increased using a method of the related art,for example, the method described in Patent Citation 3 described above.However, when the OSDA-free beta-type zeolite is treated using thepresent manufacturing method, the breaking of the crystal structure isextremely suppressed so that the Si/Al can be increased.

As a synthesizing method of the OSDA-free beta-type zeolite, it ispossible to employ, for example, the method described in the pamphlet ofthe International Publication No. 2011/013560. In addition, it ispossible to employ the method described in the specification of ChinesePatent Application Laid-Open No. 101249968A. Furthermore, it is alsopossible to employ the method described in Chemistry of Materials, Vol.20, No. 14, p. 4533 to 4535 (2008).

An example of the synthesizing method of the OSDA-free beta-type zeoliteis as follows.

(i) A silica source, an alumina source, an alkali source and water aremixed so as to form a reaction mixture having a composition indicated bythe molar ratios shown below,

SiO₂/Al₂O₃=40 to 200, particularly 44 to 200

Na₂O/SiO₂=0.22 to 0.4, particularly 0.24 to 0.35

H₂O/SiO₂=10 to 50, particularly 15 to 25

(ii) A beta-type zeolite not including an organic compound which has aSiO₂/Al₂O₃ ratio of 8 to 30 and an average particle diameter of 150 nmor more, particularly, 150 nm to 1000 nm, and more particularly 200 nmto 600 nm, is used as a seed crystal, the beta-type zeolite is added tothe reaction mixture at a proportion of 0.1 mass % to 20 mass % withrespect to the silica component in the reaction mixture, and

(iii) the reaction mixture to which the seed crystal is added isenclosure-heated at 100° C. to 200° C., particularly 120° C. to 180° C.

In the ion exchange of the raw material beta-type zeolite, an ammoniumcompound is used, and, particularly, use of ammonium nitrate, ammoniumchloride, ammonium acetate or ammonium sulfate is preferable. In a casein which the ion exchange is carried out using an ammonium compound,such as ammonium nitrate or ammonium chloride, an aqueous solutionhaving a concentration of ammonium ion of 0.1 mol/L to 10 mol/L ispreferably added to 10 g of the raw material beta-type zeolite at 25 mLto 1000 mL, preferably at 100 mL to 1000 mL, and particularly at 400 mLto 600 mL. The ion exchange can be carried out in a state in which theaqueous solution including ammonium ions is heated or not heated. In acase in which the aqueous solution including ammonium ions is heated,the heating temperature is set to 40° C. to 100° C., and particularlypreferably set to 70° C. to 90° C. The raw material beta-type zeolite isdispersed in the aqueous solution including ammonium ions so as to forma dispersion liquid, and this state is held for a predetermined time,thereby carrying out the ion exchange. The holding time is set to 1 hourto 48 hours, and particularly preferably set to 12 hours to 24 hours.The dispersion liquid may be in a static state or in a stirred state.

After the dispersion liquid is held for a predetermined time, thedispersion liquid is filtered, the raw material beta-type zeolite isseparated, and water washing is carried out. If necessary, a combinationof the ion exchange treatment and water washing may be repeated aplurality of times. After the ion exchange treatment is carried out inthe above manner, the raw material beta-type zeolite is dried, and anammonium-type beta-type zeolite is obtained. This ammonium-typebeta-type zeolite has, accordingly, an extremely reduced content ofalkali metal ions.

(2) A Process of Exposing the Ion-Exchanged Raw Material Beta-TypeZeolite to Water Vapor

In order to expose the ammonium-type raw material beta-type zeolite towater vapor, for example, the raw material beta-type zeolite may bestatically placed in a water vapor atmosphere, or the raw materialbeta-type zeolite may be disposed in a water vapor stream. Specifically,it is possible to expose the raw material beta-type zeolite to watervapor using an apparatus shown in FIG. 1. The apparatus 10 shown in thesame drawing has a holding tube 11 in which the raw material beta-typezeolite is held. Both ends of the holding tube 11 are opened. The bottomend portion 11 a is open to the atmosphere. The top end portion 11 b ofthe holding tube 11 serves as an inlet of water vapor, and is connectedto a water vapor supply source 12 and an inert gas supply source 13. Thewater vapor supply source 12 is configured of a bottomed chassis 12 aopened at the top end portion. An end portion of a bubbling tube 12 b ofinert gas is inserted into the chassis 12 a. The other end portion ofthe bubbling tube 12 b is connected to the inert gas supply source (notshown in the drawing). Furthermore, water 14 is stored in the chassis 12a. The height of water surface is higher than the location of the endportion of the bubbling portion 12 b which is inserted into the bottomedchassis 12 a. Heating means 15 is disposed around the holding tube 11.The heating means 15 can heat the raw material beta-type zeolite held inthe holding tube 11 and water vapor circulating in the holding tube 11.An inert gas, such as argon, is supplied from the inert gas supplysource 13, and the inert gas is bubbled through the bubbling tube 12 bin the water vapor supply source 12, thereby supplying a predeterminedamount of water vapor to the holding tube 11. The supply amount of watervapor is determined by the balance of the supply amount of the inert gasin the inert gas supply source 13 and the water vapor supply source 12.Water vapor supplied to the holding tube 11 is heated by using theheating means 15 along with the raw material beta-type zeolite. Inaddition, the raw material beta-type zeolite is exposed to water vaporheated to a predetermined temperature. It is considered that thisexposure detaches aluminum atoms which compose the raw materialbeta-type zeolite from predetermined sites in the crystal lattice, andsilicon atoms migrate into the detached sites. However, at a point intime when the raw material beta-type zeolite is exposed to water vapor,the Si/Al ratio in the raw material beta-type zeolite is not changed. Inaddition, when the raw material beta-type zeolite is exposed to watervapor, the zeolite is transformed from the ammonium type to a protontype.

The temperature of the water vapor used for the exposure of the rawmaterial beta-type zeolite is preferably set to 150° C. to 1000° C.,more preferably set to 500° C. to 900° C., and particularly preferablyset to 500° C. to 800° C. since it is possible to accelerate detachmentof aluminum while suppressing breaking of the crystal structure of thezeolite. For the same reason, in a case in which the temperature of thewater vapor is within the above range, the exposure time of the watervapor is preferably set to 1 hour to 48 hours, more preferably set to 1hour to 24 hours, and particularly preferably set to 12 hours to 24hours. The pressure (partial pressure) of the water vapor at a point intime when the raw material beta-type zeolite and the water vapor comeinto contact is the atmospheric pressure or lower since the bottom endportion of the holding tube 11 is open. The preferable partial pressureof the water vapor is 1 kPa to 101.3 kPa.

(3) An Acid Treatment Process of the Raw Material Beta-Type Zeolitewhich has been Exposed to Water Vapor

The raw material beta-type zeolite which has been exposed to water vaporis subjected to an acid treatment, which generates dealuminum from thebeta-type zeolite. As the acid used in the acid treatment, a variety ofmineral acids are preferably used. For example, it is possible to use anitric acid, a sulfuric acid, a hydrochloric acid or the like. As theconcentration of the acid increases when the acid treatment is carriedout, dealumination proceeds so that the Si/Al ratio of the beta-typezeolite increases. Therefore, in order to obtain a beta-type zeolitehaving a desired Si/Al ratio, it is a simple means to adjust theconcentration of the acid. From the above viewpoint, while varyingdepending on the kind of the acid used, in many cases, the concentrationof the acid is preferably 0.1 mass % to 100 mass %, and particularlypreferably 0.1 mass % to 60 mass %. For example, in a case in which anitric acid is used as the mineral acid, the concentration of the nitricacid is preferably 0.1 mass % to 70 mass %, and particularly preferably0.5 mass % to 5 mass %. In a case in which a nitric acid is used as themineral acid, the concentration of the nitric acid is preferably 0.01mol/L to 21 mol/L, and particularly preferably 0.05 mol/L to 14 mol/L interms of a mole concentration. Meanwhile, when the concentration of theacid is high, while dealumination proceeds as described above,accordingly, the crystal structure of the zeolite is liable to bebroken. Particularly, in a case in which the OSDA-free beta-type zeoliteis used as the raw material, the crystal structure is liable to bebroken. However, in the invention, since the water vapor exposuretreatment is carried out prior to the acid treatment, even in a case inwhich the OSDA-free beta-type zeolite is used as the raw material, andthe treatment is carried out using an acid having a high concentration,the crystal structure of the zeolite is not easily broken.

The amount of the acid used in the acid treatment is 5 mL to 500 mL,preferably 10 mL to 500 mL, and particularly preferably 100 mL to 200 mLper 1 gram of the raw material beta-type zeolite when the acid has theabove concentration since efficient dealumination is caused. The acidtreatment may be carried out with heating or without heating. In a casein which the acid treatment is carried out with heating, the temperatureof the acid is preferably set to 40° C. to 100° C., and particularlypreferably set to 70° C. to 90° C. in terms of efficient dealumination.In a case in which a nitric acid is used as the mineral acid, whiledepending on the concentration, the temperature of the nitric acid ispreferably set to 40° C. to 130° C., particularly preferably set to 70°C. to 130° C., and more particularly preferably set to 70° C. to 90° C.In addition, in a case in which the acid treatment is carried out withheating, the acid may be in a refluxed state. In a case in which theconcentration and temperature of the acid are within the above ranges,the time of the acid treatment is preferably set to 1 hour to 24 hours,and particularly preferably set to 2 hours to 24 hours since thebreaking of the crystal structure of the zeolite is suppressed, andefficient dealumination is carried out.

After the acid treatment is completed, solid-liquid separation iscarried out, the separated beta-type zeolite is washed with water onceor a plurality of times, and then dried. In this manner, a targetbeta-type zeolite is obtained. The beta-type zeolite obtains anincreased Si/Al ratio compared to the OSDA-free beta-type zeolite whichis used as the raw material. The beta-type zeolite has the aboveincreased Si/Al ratio, and also maintains the crystal structure.Furthermore, the beta-type zeolite maintains the substantiallyoctahedral shape of the OSDA-free beta-type zeolite. This beta-typezeolite has been transformed into a proton-type zeolite as describedabove.

A preferable manufacturing method of the MSE-type zeolite of theinvention is the same as the above preferable manufacturing method ofthe beta-type zeolite except that a raw material MSE-type zeolite isused instead of the raw material beta-type zeolite, and a zeolitesynthesized without using the organic SDA (hereinafter also referred toas “OSDA-free MSE-type zeolite”) is used as the raw material MSE-typezeolite in the above preferable manufacturing method of the beta-typezeolite.

As a synthesizing method of the OSDA-free MSE-type zeolite, it ispossible to employ, for example, the method described in the pamphlet ofthe International Publication No. 2012/002367. An example of thesynthesizing method of the OSDA-free beta-type zeolite is as follows.

(i) A silica source, an alumina source, an alkali source and water aremixed so as to form a reaction mixture having a composition indicated bythe molar ratios shown in the following (a) or (b),

(a)

SiO₂/Al₂O₃=40 to 200, particularly 44 to 200

(Na₂O+K₂O)/SiO₂=0.24 to 0.4, particularly 0.25 to 0.35

K₂O/(Na₂O+K₂O)=0 to 0.7, particularly 0.01 to 0.65

H₂O/SiO₂=10 to 50, particularly 15 to 25

(b)

SiO₂/Al₂O₃=10 to 40, particularly 12 to 40

(Na₂O+K₂O)/SiO₂=0.05 to 0.25, particularly 0.1 to 0.25

K₂O/(Na₂O+K₂O)=0 to 0.7, particularly 0.01 to 0.65

H₂O/SiO₂=5 to 50, particularly 10 to 25

(ii) A MSE-type zeolite not including an organic compound which has aSiO₂/Al₂O₃ ratio of preferably 10 to 50, particularly preferably 15 to40, and an average particle diameter of preferably 100 nm to 2000 nm,more preferably 200 nm to 1000 nm, is used as a seed crystal, thebeta-type zeolite is added to the reaction mixture at a proportion ofpreferably 0.1 mass % to 30 mass %, more preferably 1 mass % to 20 mass%, and still more preferably 1 mass % to 10 mass % with respect to thesilica component in the reaction mixture, and

(iii) the reaction mixture to which the seed crystal is added isenclosure-heated at 100° C. to 200° C., particularly at 120° C. to 180°C.

As is evident from the compositions of the above (a) and (b), a gel usedto manufacture the MSE-type zeolite may include only sodium ions as thealkali metal, or may include both sodium ions and potassium ions. When azeolite is synthesized using a gel including sodium ions and potassiumions, compared to a case in which a zeolite is synthesized using a gelincluding only sodium ions, it is advantageous since the by-productionof impurities, particularly, the generation of a small amount of abyproduct zeolite, can be further prevented. The MSE-type zeolite can besynthesized from a gel including only potassium ions, when theproportion of potassium ions increases, there is a tendency that thecrystallization rate becomes slow and the degree of crystallinity of theobtained MSE-type zeolite becomes low. As a potassium ion source, forexample, potassium hydroxide is preferably used. In addition, in orderto adjust the K₂O/(Na₂O+K₂O) ratio, as a potassium source other than theabove, a potassium salt, such as potassium chloride, potassium sulfateor potassium nitrate, may be used.

The beta-type zeolite and the MSE-type zeolite of the invention, whichare obtained in the above manners, are promising substances as a solidacid catalyst or an adsorbent, and, in more detail, are particularlypromising as a catalyst that catalytically cracks paraffin, for example,a cracking catalyst of a long-chain hydrocarbon (for example, hexane) inthe petrochemical industry. Also, the beta-type zeolite and the MSE-typezeolite are promising substances as a hydrocarbon trap for purifying theexhaust gas from an internal-combustion engine.

Thus far, the invention has been described based on the preferableembodiments, but the invention is not limited to the embodiments. Forexample, according to the above manufacturing method, it is possible topreferably manufacture the beta-type zeolite and the MSE-type zeolite ofthe invention; however, depending on the manufacturing method, it isalso possible to manufacture beta-type zeolites and MSE-type zeolitesother than the beta-type zeolite and the MSE-type zeolite of theinvention.

EXAMPLES

Hereinafter, the invention will be described in more detail usingexamples. However, the scope of the invention is not limited to theexamples. Unless otherwise described, “%” indicates “mass %”.

Example 1

(1) Synthesis of a Seed Crystal

A beta-type zeolite having a SiO₂/Al₂O₃ ratio of 24.0 was synthesized bycarrying out stirring and heating at 165° C. for 96 hours using awell-known method of the related art in which tetraethylammoniumhydroxide was used as the organic SDA, sodium aluminate was used as thealumina source, and fine powder-form silica (Mizukasil P707) was used asthe silica source. The beta-type zeolite was fired at 550° C. for 10hours in an electric furnace while circulating air, therebymanufacturing a crystal not including an organic substance. As a resultof observing the crystal using a scanning electron microscope, theaverage particle diameter was 280 nm. The crystal of the beta-typezeolite not including an organic substance was used as the seed crystal.

(2) Synthesis of an OSDA-Free Beta-Type Zeolite

Sodium aluminate (0.235 g) and 36% sodium hydroxide (1.828 g) weredissolved in pure water (13.9 g). A mixture of fine powder-form silica(Cab-O-sil, M-5, 2.024 g) and the above seed crystal (0.202 g) was addedto the aqueous solution little by little, stirred and mixed, therebyproducing a reaction mixture. In the reaction mixture, the SiO₂/Al₂O₃ratio was 70, the Na₂O/SiO₂ ratio was 0.3, and the H₂O/SiO₂ ratio was20. This reaction mixture was put into a 60 mL stainless steel closedvessel, and statically heated at 140° C. for 34 hours under anautogenous pressure without aging and stirring. After the vessel wascooled, the product was filtered and washed with warm water, therebyobtaining a white powder. As a result of carrying out an X-raydiffraction measurement on this product, it was confirmed that thebeta-type zeolite did not include impurities. As a result of acomposition analysis, the Si/Al ratio was 6.4. A scanning electronmicroscopic photograph of the beta-type zeolite is shown in FIG. 2A. Asshown in the same drawing, it is found that the beta-type zeolite has asubstantially octahedral shape.

(3) Ion Exchange Treatment

The obtained OSDA-free beta-type zeolite was used as the raw material,and was dispersed in an aqueous solution of ammonium nitrate. The massratio of the OSDA-free beta-type zeolite, ammonium nitrate, and waterwas set to 1:2:50. This dispersion liquid was statically placed over 24hours in a state of being heated at 80° C., thereby carrying out ionexchange. After that, filtration was carried out so as to separate thebeta-type zeolite. After the operation of ion exchange and filtrationwas repeated one more time, the resultant was washed with water, anddried at 80° C., thereby producing an ammonium-type beta-type zeolite.

(4) Exposure Using Water Vapor

The ammonium-type beta-type zeolite was filled into an apparatus shownin FIG. 1. The filling amount was set to 1 g. A gas mixture of argon andwater vapor was continuously circulated for 24 hours in a state in whichthe ammonium-type beta-type zeolite was heated to 700° C. by the heatingmeans 15 shown in the same drawing. The partial pressure of the watervapor was set to 12.2 kPa. The exposure using water vapor transformedthe beta-type zeolite from the ammonium-type into a proton-type.

(5) Acid Treatment

The water vapor-exposed beta-type zeolite was subjected to an acidtreatment using a 0.1 mol/L aqueous solution of nitric acid. Thetemperature of the aqueous solution of nitric acid was set to 80° C. Theaqueous solution of nitric acid (10 mL) was added to the beta-zeolite(0.1 g). The treatment was carried out for 2 hours while stirring thesolution by using a magnetic stirrer. In the above manner, a targetbeta-type zeolite was obtained. A scanning electron microscopicphotograph of the obtained beta-type zeolite is shown in FIG. 2B. Inaddition, the X-ray diffraction diagram is shown in FIG. 3. Furthermore,the Si/Al ratio obtained from an element analysis was shown in FIG. 3.As shown in FIG. 2B, it is found that the beta-type zeolite has asubstantially octahedral shape.

Examples 2 to 5

The concentrations of the aqueous solution of nitric acid used in theacid treatment of Example 1 were set to 0.5 mol/L (Example 2), 1.0 mol/L(Example 3), 2.0 mol/L (Example 4), and 8.0 mol/L (Example 5). Exceptthe above, beta-type zeolites having an increased Si/Al ratio wereobtained in the same manner as in Example 1. The X-ray diffractiondiagrams of the obtained beta-type zeolites are shown in FIG. 3. Inaddition, the Si/Al ratios obtained from element analyses were shown inFIG. 3. Meanwhile, while not shown, the beta-type zeolites obtained inthe above examples had a substantially octahedral shape. In addition,for the beta-type zeolite obtained in Example 3, the BET specificsurface area and the volume of the micro hole were measured under thefollowing conditions. The BET specific surface area obtained through themeasurement was 617 m²/g, and the volume of the micro hole was 0.17cm³/g.

(Measurement Conditions of the BET Specific Surface Area and the Volumeof the Micro Hole)

Apparatus used: Belsorp-max-1-N, apparatus for automatic adsorptionmeasurement manufactured by Bel Japan, Inc.

Measurement temperature: −196° C. (nitrogen),

Temperature of an air constant-temperature bath: 40° C.

Equilibrium adsorption time: 300 s

Sample prior treatment conditions: a heating treatment (400° C., 2 h) ina vacuum (1.33×10⁻⁴ Pa)

Comparative Example 1

A proton-type beta-type zeolite was obtained by carrying out a directthermal treatment without carrying out the exposure using water vaporand the acid treatment after ion-exchanging the OSDA-free beta-typezeolite in Example 1. The conditions of the thermal treatment were setto a temperature of 650° C., a time of 60 minutes, and an aircirculation amount of 40 cm³/min. The X-ray diffraction diagram of theobtained beta-type zeolite is shown in FIG. 3. In addition, the Si/Alratio obtained from an element analysis was shown in the same drawing.The beta-type zeolite lost the octahedral shape due to the thermaltreatment.

Comparative Example 2

(1) Synthesis of a Beta-Type Zeolite Using the Organic SDA (OSDA)

Tetraethylammonium hydroxide as the organic structure directing agent(OSDA) and an aqueous solution including sodium hydroxide were stirredat room temperature, and colloidal silica was added thereto. As thecolloidal silica, Ludox HS-40 (silica portion 40%) was used. After 30minutes of stirring from the addition of the colloidal silica, anaqueous solution of aluminum sulfate was added, and, furthermore,stirring was carried out for 30 minutes, thereby producing a gel. Thecomposition of the gel was 0.033 mole of Al₂O₃, 0.24 mole of sodiumhydroxide, 0.50 mole of tetraethylammonium hydroxide, and 20 mole ofwater with respect to 1 mole of SiO₂. This gel was put into anautoclave, and the reaction was performed over 7 days in a state ofbeing heated to 150° C. In the above manner, a beta-type zeolite wasobtained. This zeolite was heated at 550° C. for 6 hours in theatmosphere so as to decompose and remove tetraethylammonium hydroxidewhich was the OSDA. As a result of carrying out an X-ray diffractionmeasurement, it was confirmed that this product was a beta-type zeolitenot including impurities. As a result of a composition analysis, theSi/Al was 13.1. A scanning electron microscopic photograph of thebeta-type zeolite is shown in FIG. 4A. As shown in the same drawing, itis found that the beta-type zeolite has an irregular shape.

(2) ION EXCHANGE

Ion exchange was carried out under the same conditions as in Example 1.The exposure using water vapor and the acid treatment were not carriedout. After the ion exchange, a thermal treatment was carried out at atemperature of 650° C. for a time of 60 minutes and at an aircirculation amount of 40 cm³/min, thereby transforming the beta-typezeolite into a proton type. In the above manner, a beta-type zeolite wasobtained. The X-ray diffraction diagram of the obtained beta-typezeolite is shown in FIG. 5. In addition, the Si/Al ratio obtained froman element analysis was shown in the same drawing.

Comparative Example 3

In Comparative example 2, the exposure using water vapor and the acidtreatment were carried out under the same conditions as in Example 3after the ion exchange. In the above manner, a beta-type zeolite wasobtained. A scanning electron microscopic photograph of the obtainedbeta-type zeolite is shown in FIG. 4B. In addition, the X-raydiffraction diagram is shown in FIG. 5. Also, the Si/Al ratio obtainedfrom an element analysis was shown in FIG. 5. As shown in FIG. 4B, it isfound that this beta-type zeolite has an irregular shape.

(Evaluation)

For the beta-type zeolites obtained in Example 3 and Comparativeexamples 1 to 3, Evaluation 1 and Evaluation 2 of the catalytic activityduring the cracking reaction of hexane were carried out in the followingorder. Prior to Evaluation 1 and Evaluation 2, powder-form beta-typezeolite was molded and granulated. Specifically, beta-type zeolitepowder (1 g to 2 g) was filled into a tablet die having an innerdiameter of 20 mm, and then pressure-molded using an hydraulic press at0.4 MPa, thereby producing a pellet having a diameter of 20 mm. Thispellet was ground to an appropriate extent on a sieve, granulated into500 μm to 600 μm, and used as a catalyst.

(Evaluation 1)

A catalytic reaction was carried out using a fixed-bed normal pressurecirculation reaction apparatus. The schematic view of the apparatus isshown in FIG. 6. Hexane, which was a reactant, was supplied from asyringe using a syringe pump, and introduced into a nitrogen (1%)-argongas mixture, which was a carrier gas. Since the hexane supplied from thesyringe pump was introduced into a vaporizing chamber heated in advance,the hexane was vaporized so as to become gas, and this gas was made toaccompany the carrier gas. The condensation of the vaporized hexane wasprevented by heating the gas line of a reaction apparatus from theoutside at an appropriate temperature using a stainless steel pipehaving an inner diameter of 2 mm and a heater. A quartz tube having aninner diameter of 8 mm was used as a reaction tube, the previouslygranulated beta-type zeolite catalyst (100 mg) was filled into thequartz tube, and a catalyst layer was held at the central portion of thereaction tube using silica wool. As a reaction pretreatment, thetemperature of the beta-type zeolite catalyst was increased up to 650°C. at a temperature-increase rate of 7° C./min under air circulation,and the beta-type zeolite was held for 1 hour in this atmosphere. Afterthat, the circulated gas was switched to helium, and then thetemperature of the reaction tube was decreased to 450° C. at 5° C./min.After it was confirmed that the beta-type zeolite was stabilized at 450°C., a methane-helium gas mixture accompanied by hexane was supplied tothe catalyst layer, and a catalytic reaction was begun. The partialpressure of the hexane was 5.0 kPa. After 5 minutes elapsed from thebeginning of the reaction, a hexagonal valve was switched so as tointroduce reaction products stored in a sampling roof into a gaschromatograph, the reaction products were separated by using a capillarycolumn, and the properties and quantities of the respective products andunreacted substances were measured by using a flame ionization detector(FID). After a predetermined time (70 minutes) elapsed, the supply ofhexane to the catalyst layer was stopped, and the circulated gas wasswitched to helium. After that, the temperature was increased up to 500°C. at 1° C./min to 2° C./min, the hexane was supplied again when thetemperature was stabilized, and the catalytic reaction was carried out.The same operation was subsequently carried out at 550° C. an 600° C.The W/F during the catalytic reaction was set to 19.8 g-catalyst h(mol-hexane)⁻¹ in all reaction temperatures. After the catalyticreaction at 600° C. was stopped, the beta-type zeolite was naturallycooled under helium circulation. The results are shown in Table 5 andFIG. 7 below. The selection rates into the respective products wereobtained based on carbon (carbon atom-converted). The propylene (C₃═)yield was obtained from “the inversion rate×the selection rate intopropylene (C₃═)”. Meanwhile, the reaction temperature was measuredbetween the heater installed so as to heat the quartz reaction tube ofthe fixed-bed normal pressure circulation reaction apparatus from theoutside, and the reaction tube.

TABLE 5 Temperature TOS Inversion Selection rate into the respectiveproducts (mol %) Substance C₃ = yield Catalyst (° C.) (min) rate (%) C₁C₂ = C₂ C₃ = C₃ C₄ C₅ Aromatic yield (%) (C %) Example 3 450 5 8.3 4.16.7 9.4 47.2 20.5 12.2 0.0 0.0 97.0 4.0 500 5 20.1 4.7 8.9 9.3 45.8 17.712.7 0.7 0.2 99.6 9.6 550 5 51.3 6.5 12.6 7.8 45.8 14.3 11.7 0.5 0.898.1 24.5 600 5 85.1 12.2 19.6 6.0 39.9 12.0 8.1 0.3 1.9 91.2 35.0Comparative 450 5 54.0 2.8 10.5 2.0 24.9 40.8 15.7 1.6 1.8 91.2 11.9example 1 500 5 57.1 6.0 14.3 5.1 30.0 28.0 13.1 0.6 2.8 89.0 15.6 550 556.0 8.0 15.4 6.2 37.7 17.6 11.1 0.3 3.7 85.5 18.9 600 5 47.4 10.5 18.16.3 40.1 8.6 10.1 0.2 6.0 83.1 16.7 Comparative 450 5 60.3 2.9 10.5 2.122.2 41.8 16.9 1.6 1.9 95.1 12.4 example 2 500 5 64.4 6.5 14.1 5.5 26.531.9 12.2 0.5 2.8 91.7 16.1 550 5 76.9 10.5 17.8 7.5 27.4 22.7 9.1 0.34.7 85.0 19.2 600 5 74.3 12.6 21.1 7.4 33.5 11.3 6.5 0.1 7.5 88.9 24.0Comparative 450 5 7.5 4.0 6.0 10.1 49.2 20.2 10.5 0.0 0.0 93.7 3.6example 3 500 5 19.0 4.4 7.3 9.3 46.8 17.0 12.4 2.8 0.0 86.1 7.8 550 536.6 5.1 9.7 8.4 47.9 14.8 12.4 0.7 0.8 78.6 14.3 600 5 67.7 7.3 13.56.9 48.0 12.2 10.4 0.4 1.4 61.4 21.4

(Evaluation 2)

In Evaluation 1, the reaction temperature was fixed at 600° C., and thereaction products were introduced into the gas chromatography after fiveminutes elapsed from the beginning of the reaction, after 55 minuteselapsed, after 105 minutes elapsed, and after 155 minutes elapsed, thereaction products were separated by using a capillary column, and theproperties and quantities of the respective products and unreactedsubstances were measured by using a flame ionization detector (FID).Except the above, Evaluation 2 was carried out in the same manner as inEvaluation 1. In addition, the time dependency of the inversion rate wasobtained. The results are shown in FIG. 8.

As is evident from the results shown in Table 5 and FIGS. 7 and 8, it isfound that, when the beta-type zeolite obtained in Example 3 is used asa catalyst, and cracking of hexane is carried out, C₃═ (propylene),which is a useful substance as a chemical raw material, is generated ata high yield. In addition, it is also found that deactivation of thebeta-type zeolite is not observed. In contrast to the above, in thebeta-type zeolite of Comparative example 1, which had a substantiallyoctahedral shape, but had a low Si/Al ratio, and the beta-type zeoliteof Comparative example 2, which had a high Si/Al ratio, but had anirregular shape, the yields of C₃═ (propylene) were lower than that ofExample 3. Furthermore, deactivation was observed. In the beta-typezeolite of Comparative example 3, which had an extremely high Si/Alratio, but had an irregular shape, the yield of C₃═ (propylene) wasfavorable, but aging deactivation was observed in the reaction at 600°C.

Examples 6 to 18

Beta-type zeolites were obtained in the same manner as in Example 1except that the manufacturing conditions described in Table 6 below wereemployed. The X-ray diffraction diagrams of the beta-type zeolitesobtained in Examples 6 to 8 are shown in FIG. 9. The X-ray diffractiondiagrams of the beta-type zeolites obtained in Examples 9 to 16 areshown in FIG. 10. The X-ray diffraction diagrams of the beta-typezeolites obtained in Examples 17 and 18 are shown in FIG. 11. Inaddition, the Si/Al ratios obtained from element analyses were describedin the drawings. Meanwhile, while not shown, the beta-type zeolitesobtained in Examples 6 to 18 had a substantially octahedral shape. Table6 below also describes the manufacturing conditions employed in Examples1 to 5.

TABLE 6 Conditions of the water vapor Conditions of the acid treatmentprocess exposure process Concentration Temperature (° C.) Exposure time(h) (mol/L) Temperature (° C.) Time (h) Example 1 700 24 0.1 80 2Example 2 0.5 Example 3 1.0 Example 4 2.0 Example 5 8.0 Example 6 8.0130 (*) 2 Example 7 8.0 24 Example 8 13.4 Example 9 150 0.1 80 2 Example10 250 Example 11 350 Example 12 450 Example 13 550 Example 14 650Example 15 750 Example 16 850 Example 17 700 2 0.1 Example 18 6 (*) InExamples 6 to 8, the acid treatment is carried out by refluxing an acidin an oil bath at 130° C., and “130° C.” described herein refers to thetemperature of the oil bath.

From the results in the X-ray diffraction diagrams of Examples 1 to 8shown in FIGS. 3 and 9, it is found that, when the concentration of theacid is increased, or the time of the acid treatment is extended in theacid treatment process, the Si/Al ratio of the beta-type zeoliteincreases. On the other hand, it is found that, even when theconcentration of the acid is increased up to 13.4 mol/L, and the time ofthe acid treatment is extended up to 24 hours, the breaking of thecrystal structure of the beta-type zeolite does not occur. In addition,from the results in the X-ray diffraction diagrams of Examples 9 to 16in FIG. 10, it is found that, particularly, in the water vapor exposureprocess, in a case in which the temperature of the water vapor is 550°C. to 750° C. (Examples 13 to 15), more of the crystal structure of thebeta-type zeolite is maintained compared to a case in which thetemperature of the water vapor is 150° C. to 450° C., which is a lowertemperature than the above temperature (Examples 9 to 12). In addition,from the results in the X-ray diffraction diagrams of Examples 3, 17 and18 shown in FIGS. 3 and 11, it is found that, in a case in which thetime of the water vapor exposure is shortened to 2 hours (Example 17) or6 hours (Example 18) from 24 hours (Example 3), the Si/Al ratio of thebeta-type zeolite decreases, but there is no change in thecrystallinity.

Example 19

(1) Synthesis of a Seed Crystal

N,N,N′,N′-tetraethylbicyclo[2.2.2]-oct-7-ene-2,3:5,6-dipyrrolidiniumdiiodide was used as the organic SDA. According to the description inthe specification of U.S. Pat. No. 6,049,018, a reaction mixture wasprepared using aluminum hydroxide as the alumina source, colloidalsilica as the silica source, and potassium hydroxide as the alkalisource, and was heated at 160° C. for 16 days using a static method. AMSE-type zeolite obtained by heating and firing the product in the airat 540° C. for 8 hours was used as the seed crystal. The Si/Al ratio was12.0. The crystal of the MSE-type zeolite not including an organicsubstance was used as the seed crystal.

(2) Synthesis of the OSDA-Free MSE-Type Zeolite

Sodium aluminate (0.096 g) and 36% sodium hydroxide (2.147 g) weredissolved in pure water (10.74 g), thereby producing an aqueoussolution. A mixture of fine powder-form silica (Cab-O-sil, M-5, 2.022 g)and the seed crystal (0.202 g) was added to the aqueous solution littleby little, stirred and mixed, thereby producing a reaction mixture. Inthe reaction mixture, the SiO₂/Al₂O₃ ratio was 100, the (Na₂O+K₂O)/SiO₂ratio was 0.3, the K₂O/(Na₂O+K₂O) ratio was 0, and the H₂O/SiO₂ ratiowas 20. A mixture of this reaction mixture and the seed crystal was putinto a 60 cc stainless steel closed vessel, and statically heated at140° C. for 60 hours under an autogenous pressure without aging andstirring. After the closed vessel was cooled, the product was filteredand washed with warm water, thereby producing white powder. As a resultof carrying out an X-ray diffraction measurement on this product, it wasconfirmed that the product was a MSE-type zeolite. As a result of acomposition analysis, the Si/Al ratio was 6.8.

(3) Ion Exchange Treatment

The obtained OSDA-free MSE-type zeolite was used as the raw material,and was dispersed in an aqueous solution of ammonium nitrate. The massratio of the OSDA-free beta-type zeolite, ammonium nitrate, and waterwas set to 1:2:50. This dispersion liquid was statically placed over 24hours in a state of being heated at 80° C., thereby carrying out ionexchange. After that, filtration was carried out so as to separate thebeta-type zeolite. After the operation of ion exchange and filtrationwas repeated one more time, the resultant was washed with water, anddried at 80° C., thereby producing an ammonium-type MSE-type zeolite.

(4) Exposure Using Water Vapor

The ammonium-type MSE-type zeolite was filled into the apparatus shownin FIG. 1. The filling amount was set to 1 g. A gas mixture of argon andwater vapor was continuously circulated for 24 hours in a state in whichthe ammonium-type MSE-type zeolite was heated at 700° C. by the heatingmeans 15 shown in the same drawing. The partial pressure of the watervapor was set to 12.2 kPa. The exposure using water vapor transformedthe MSE-type zeolite from the ammonium-type into a proton-type.

(5) Acid Treatment

The water vapor-exposed beta-type zeolite was subjected to an acidtreatment using a 6.0 mol/L aqueous solution of nitric acid. Thetemperature of the aqueous solution of nitric acid was set to 80° C. Theaqueous solution of nitric acid (10 mL) was added to the MSE-zeolite(0.1 g). The treatment was carried out for 2 hours while stirring thesolution using a magnetic stirrer. In the above manner, a targetMSE-type zeolite was obtained. The X-ray diffraction diagram of theobtained beta-type zeolite is shown in FIG. 12. The Si/Al ratio obtainedfrom an element analysis was 62.9.

Comparative Example 4

A proton-type MSE-type zeolite was obtained by carrying out a directthermal treatment without carrying out the exposure using water vaporand the acid treatment after ion-exchanging the OSDA-free MSE-typezeolite in Example 19. The conditions of the thermal treatment were setto a temperature of 650° C., a time of 60 minutes, and an aircirculation amount of 40 cm³/min. The X-ray diffraction diagram of theobtained MSE-type zeolite is shown in FIG. 12. In addition, the Si/Alratio obtained from an element analysis was 6.5.

Comparative Example 5

A proton-type MSE-type zeolite was obtained by carrying out a directthermal treatment without carrying out the acid treatment afterion-exchanging the OSDA-free MSE-type zeolite, and then exposing thezeolite using water vapor in Example 19. The conditions of the thermaltreatment were set to a temperature of 650° C., a time of 60 minutes,and an air circulation amount of 40 cm³/min. The X-ray diffractiondiagram of the obtained MSE-type zeolite is shown in FIG. 12. Inaddition, the Si/Al ratio obtained from an element analysis was 6.8.

(Evaluation)

For the MSE-type zeolites obtained in Example 19 and Comparativeexamples 4 and 5, evaluation of the catalytic activity during thecracking reaction of hexane was carried out according to Evaluation 2described above. The time dependency of the inversion rate is shown inFIG. 13. In addition, the selection rates into the respective productsand the yield of propylene are shown in Table 7.

TABLE 7 C₃ = Temperature TOS Inversion Selection rate into therespective products (mol %) yield Catalyst (° C.) (min) rate (%) C₁ C₂ =C₂ C₃ = C₃ C₄ = C₄ C₅ = C₅ Aromatic (C %) Example 19 600 5 31.5 10.818.3 6.4 44.1 6.6 7.7 3.6 1.2 0.5 0.8 13.5 55 29.5 10.7 17.6 5.9 45.76.8 7.4 3.6 1.2 0.4 0.7 15.1 105 28.3 10.8 17.6 5.9 45.5 7.0 7.4 3.6 1.30.4 0.7 14.7 155 28.2 10.8 17.8 6.0 45.2 7.0 7.4 3.5 1.4 0.4 0.6 13.6Comparative 600 5 92.8 17.5 27.3 6.5 26.8 10.6 2.9 1.5 0.0 0.1 6.9 19.8example 4 55 9.9 21.7 36.3 4.7 22.8 1.4 10.4 0.4 1.4 0.9 0.0 2.2 10514.7 21.5 39.2 3.7 22.8 1.3 9.5 0.0 1.0 1.0 0.0 1.9 155 12.0 21.8 37.24.7 22.3 1.2 10.2 0.3 1.3 1.0 0.0 2.2 Comparative 600 5 62.9 11.7 22.25.3 38.0 4.9 10.4 2.0 0.3 0.3 5.0 21.7 example 5 55 47.9 11.6 22.9 5.236.7 4.6 11.2 2.0 0.4 0.4 5.1 15.7 105 43.2 12.6 23.2 5.1 35.8 4.1 12.01.9 0.6 0.5 4.3 11.9 155 35.0 13.8 23.6 4.9 33.8 3.6 12.9 1.7 0.8 0.64.3 8.1

As is evident from the results shown in FIG. 13 and Table 7, it is foundthat, when the MSE-type zeolite obtained in Example 19 is used as acatalyst, and cracking of hexane is carried out, C₃═ (propylene), whichis a useful substance as a chemical raw material, is generated at a highyield. In addition, it is also found that the deactivation of theMSE-type zeolite is not observed. In contrast to the above, in theMSE-type zeolite of Comparative example 4, in which only the ionexchange treatment was carried out, and the MSE-type zeolite ofComparative example 5, in which only the ion exchange treatment and thewater vapor exposure process were carried out, and the acid treatmentwas not carried out, the yields of propylene was low, and deactivationwas observed.

EXPLANATION OF REFERENCE

-   10 WATER VAPOR EXPOSURE APPARATUS-   11 HOLDING TUBE-   12 WATER VAPOR SUPPLY SOURCE-   13 INERT GAS SUPPLY SOURCE-   14 WATER-   15 HEATING MEANS

The invention claimed is:
 1. A MSE-type zeolite which has a Si/Al ratioof 5 or more, is a proton-type zeolite, and is obtained by transforminga raw material MSE-type zeolite synthesized without using a structuredirecting agent into an ammonium-type zeolite through ion exchange,then, exposing the MSE-type zeolite to water vapor, and subjecting theexposed MES-type zeolite to an acid treatment.
 2. The MES-type zeoliteaccording to claim 1, wherein the Si/Al ratio is 40 or more.
 3. Acatalytic cracking catalyst of paraffin including the MES-type zeoliteaccording to claim
 1. 4. A manufacturing method of a MSE-type zeolite inwhich a raw material MSE-type zeolite is transformed into anammonium-type zeolite through ion exchange, then, exposed to watervapor, and subjected to an acid treatment, thereby obtaining a MSE-typezeolite having an increased Si/Al ratio, wherein a MSE-type zeolitesynthesized without using a structure directing agent is used as the rawmaterial MSE-type zeolite to be ion-exchanged.
 5. The manufacturingmethod according to claim 4, wherein the ion-exchanged raw materialMSE-type zeolite is exposed to water vapor at 150° C. to 1000° C. for 1hour to 48 hours.
 6. The manufacturing method according to claim 4,wherein the raw material MSE-type zeolite which has been exposed towater vapor is subjected to an acid treatment at 40° C. to 100° C. for 1hour to 24 hours using a mineral acid.
 7. The manufacturing methodaccording to claim 4, wherein a MSE-type zeolite having a Si/Al ratio of5 or more is obtained.